It’s too difficult to write a 1,000-word scientific essay. Tell me the answer.

Magic Convex Lens

One day in the summer of 2005, I was leisurely staying at home and felt bored, so I found a convex lens and started playing with it. For a while, the spider plant was enlarged and turned into a huge bush; for a while, the small fish was enlarged and turned into a huge "shark"...

Soon, I got tired of playing, so I casually put the convex lens on the table. . After a while, my mother came to see me. When she saw the convex lens on the table, she hurriedly put it away and said to me: "Dongdong, don't put the convex lens in a place exposed to direct sunlight in the future. It can easily catch fire." "

After hearing this, I thought to myself, why can convex lenses make objects catch fire? I asked: "Mom, how can a convex lens cause an object to catch fire?" My mother replied: "Because the convex lens has a converging effect on light, sunlight can be regarded as parallel light, and the parallel light will converge to one point after passing through the convex lens. That is the focus. This generates a large amount of energy and can burn flammable objects when it reaches a certain temperature.”

After hearing what my mother said, I was a little skeptical. So I decided to do an experiment myself!

I first laid the paper flat on the ground, and then used a convex lens to focus the light on the paper. But the light just didn't listen to me. I wanted it to come together, but it spread out like a broom star. But I was still patient, leaning a little to the left and then to the right. Finally, I succeeded in condensing the sunlight into a small point of light. The paper didn't burn for a while, so I thought, could it be that the sun wasn't hot enough? So I touched the paper with my hand, wow! Almost burned my hand.

I had to go home first. Later, I found out from the book: "White objects easily reflect light, while black objects easily absorb light!"

I was so happy that I decided to use black paper for the second experiment. Like the first experiment, I first laid the paper flat on the ground, and then skillfully adjusted the angle to the best position, so that the sunlight turned into a small dot. I waited for a while, and the paper started to burn.

I finally understood: It turns out that the sun's rays can really burn paper when they are gathered together, it just takes some time. My mother also told me why it takes some time before it burns. It turns out that it is because the object will not burn until it reaches its ignition point.

I think if I forget to bring matches when I go out for a picnic in the future, I can use a convex lens to light a fire.

Ah! I finally understand why convex lenses can make objects catch fire

Why the loach didn’t die

In science class, the teacher assigned an assignment and asked each of our classmates to make an ecological bottle , that is, "put a small amount of plants, animals that feed on these plants, and other non-biological substances into a sealed bottle to form an artificially simulated micro-ecosystem." When I heard this, I was very interested in this experiment. I found an empty oil can, cut off the upper part, washed it, filled it with water, put a layer of mud on the bottom of the water, put some duckweed on the water surface, and put a few small loaches I bought into the water. Inside, they suddenly got into the mud, and after a while they came out for air, making the pot of water turbid, so naughty.

In the first few days, I was very enthusiastic and observed several times every day. However, gradually, there were new experiments, and I forgot about it. After a long time, a classmate talked about his ecological bottle, and I suddenly remembered that I had not observed my ecological bottle for a long time. I thought that my poor loaches must have died of thirst. After school, I hurried home, put down my schoolbag and went to look at my ecological bottle. When I saw it, I was shocked. There was almost no water in the bottle, and there was no sign of the loach. I thought the loach must be dead. Just when I was feeling sad, I suddenly saw bubbles on the surface of the mud. Could it have been blown by a loach? I quickly found a small stick and dug out the mud. Hey, a loach came out. "Yeah, the loach is still alive, the loach is still alive." I shouted happily. However, I felt very strange, so I asked my mother why the loach could survive without cement. My mother smiled and shook her head, and I had to go to the computer for help.

After some searching, I finally figured it out. It turns out that loaches breathe through their intestines when they leave the water and live in the mud. Its intestines are connected to the esophagus and anus to form a short straight tube. The intestines are covered with many capillaries that absorb oxygen from the air.

When it breathes through its intestines, the carbon dioxide and other gases produced are expelled from the anus like "farts", so many bubbles often emerge from the mud.

Oh, that’s it. No wonder the loach didn’t die in the mud without water. I'm so happy that due to my carelessness, I unexpectedly gained this knowledge about loaches.

Why does my kitten eat grass?

A few days ago, my mother bought me a kitten. The color is very beautiful and very cute. Our whole family loved it.

I often secretly hide my pocket money and go to a small shop to buy dried fish. When I come back, I give the dried fish to the kitten. The kitten eats it very quickly and eats a dried fish in one go. After eating, he happily climbed up the tree and came down again. Meowing "meow", I gave it another piece of dried fish, and the kitten finished it quickly. The next morning, I saw the kitten huddled in a corner, still shivering. I thought it was hungry, so I quickly gave it a piece of dried fish, but the kitten looked at it and didn't eat it. It just lay there motionless. move. I went to school. I was very sad and distraught at school. I was worried about the kitten at home. Finally, after school, I hurried home and found that the kitten was eating a kind of grass that I didn't know the name of. Do cats also eat grass? I couldn't believe it. Suddenly, the cat vomited out the dried fish it had eaten. I thought the cat had food poisoning, so I quickly asked my mother. My mother said, "Go and check One Hundred Thousand Whys!" I quickly checked. , I finally found out that the cat will cure itself. It eats grass to cure food poisoning. I am very happy. I not only solved a problem, but also understood a truth: If you encounter a problem that you don’t understand in life, you should Check more information and use your own practical actions to solve the problem.

Primary school student profile: Huang Jiaping, 10 years old, male, usually likes painting, reading, and doing scientific research.